Method of production of ddt



Patented M. 21, 1950 s 2 5 951 UNITED STATES PATENT OFFICE METHOD OF PRODUCTION OF DDT Walter H. C. Rueggeberg and Walter- A. Cook, United States Army I s Serial No. 564,300 7 Claims. (Cl. 260-649) (Granted under the act of March 3, 1883, an

amended April 30, 1928; 370 0. G. 757) '1 1 2 The invention described herein may manufactured and used by or for the government for (2) Cohen-080mg O governmental purposes without the payment to H us of any royalty thereon. cc

This invention relates, generally, to condensah H O] tion type reactions wherein aryl compounds are I H condensed with aldehydes, and relates, partica) CCh-CHOQ] ularly, to a new and improved method oi proi ducing DDT [2, 2-bis (p-chlorophenyl) 1,1,1-trichlorethane]. 10 l moo! Hi0 DDT has been found to be an excellent insecticide and has been widely used by military iorces 50:-0H in jungle theatres and in the tropics. To date, 4) (3014156 the production of DDT, (2,2-bis(p-chlorphenyl) a OH- 01 1,1,l-trichloroethane) depends upon the employ- $0103 ment of large volumes of 98% HQSOA in order to effect the condensation between anhydrous Cele-CHOW :50 chloral (CClaCHO) and chlorbenzene (CeHsCl). The chemical literature contains several references to condensations of this type where some aryl compound is condensed with an aldehyde to 1 gfg f g i g a g 523 2 3 532x Reaction 3, above, for two reasons, is believed mg acetaldh'yde (cHscHo) with benzene to to be responsible for the necessity of using large form 1 1 diphenylethane using however 600 quantities mncentrated msoe- First a huge grams concentrated Hzol for every 0 ofi'mols 25 excess of concentrated H2804 nullifies the dilution of paraldehyde ((CHSCHO)3) This type of com effect of the acid by the water formed and second, densation conducted in the presence of a large the reversibility of Equation 3 is minimized by the excess of concentrated H2804 is still being conremtova of H20 through a large excess of ducted today, specifically in the synthesis of DDT. gfi fg The ob ect of this invention, generally stated, is use i g gfigfi 22;; 3 8 ogf by f: the provision of an improved method of carrying & c out condensation type reactions between aryl 3 2$; i 3223:122 gg xg tlg g gd compounds and aldehydes. 01m a 9 Specifically, the object of this invention is the vantage 1n the use of chlol'sulfonic acid 13 the provision of a new and improved method of fact that chloit'ial hydrate (CC13CH(OH)2, a ar gise ssttthttcittr at is h c ore ane] c arac erized eng more e a commerc a cient and cheaper, than present methods of mak- Product) which would v to b prepared sepaing DDT. The superiority of the method of mak- 4o retely m hloral hydrate y t e r qu quening DDT according to this invention is in part tity Of concentrated H280 in excess Of redue to the elimination of the use of the large quired for the 2804 in th T co d s ti n.

volumes of concentrated sulphuric acid heretodescribed V fore required, and the utilization 01 small quan- The action of chlorsullonic acid is described titles of chlorsulfonic acid in place thereof. in the following S Of q ions:

Other objects of the invention will, in part, be (FSOFOH obvious, and will, in part, appear hereinafter. 1

For a more complete understanding of the 'fi CISO'H Col- H H0] nature and scope of this invention, reference may H be had to the following detailed description thereof, wherein a presently preferred embodi- 001 CH mentof practicing the invention is fully described. 3

Numerous experiments have led to the concOh oHOl +3180. cluslon that the role played by H2304 in the I DDT synthesis is one of specific catalysis rather than one of simple dehydration. The mecha- OQIPCHOOI (mom nism for the action of H2804 appears to be as rouowsz H 1 ooh-onOci no: coho-n H-O-SOs-O-H ooh-on-o-soion w ooh-choc! +001 lsoion cot-(moon mam As exemplified by these reactions, the quantities of acid used are metathetical, there is no elimination of water, as such, and the reaction proceeds by the evolution of gaseous HCl and the formation 01' anhydrous H2804.

A presently preferred method of carrying out the invention in the production of DDT is as follows:

82.7 parts by weight of chloral hydrate are placed in a suitable reaction vessel provided with thermometer, stirrer, dropping funnel, and gas outlet tube. From the dropping funnel, 58.3 parts by weight of commercial chlorsulfonic acid are added slowly, keeping the temperature between C. and 10 C. and avoiding a too violent evolution of HCl gas. After the addition of chlorsulfonic acid is complete. the mixture is allowed to stir at 10-20 C. until all of the chloral hydrate crystals have dissolved. 112.6 parts by weight of chlorbenzene are added to the reaction vessel at a rate slow enough so the reaction mixture remains at 20 C. This addition requires about -10 minutes. An additional 58.3 parts by weight of chlorsulionic acid are then added dropwise from the dropping funnel over a period oi! approximately 2 hours, at which time a heavy precipitation of the DDT has become visible. Stirring is continued for an additional 3-5 hours. When the reaction is complete, 200 parts by weight of an ice-H2O mixture is added and the product filtered of! on a Buchner funnel. Air is allowed to draw through the funnel for an additional 12 hours. Yield, crude DDT=94.5 g.

Since recrystallization from ethanol results in the loss of approximately 35% of the product, to the mother liquor, the crude DDT may instead be iurther purified by washing with a 1% aqueous solution of a wetting agent (such as Aerosol OT or Tergitol 4 or 7) 1 By steam distilling the oily layer of the filtrate, mentioned above, an additional 10-15% of DDT may be recovered from the residue thus bringing the total yield to 63-68%.

This invention may also be carried out at temperatures less than or greater than the 10-20 C. temperature range set forth in the presently preferred method. For example, temperatures varying between -5 C. and 39 C. yielded the following results:

It is believed that this invention may be conducted at any temperature from 0 C. or lower and 50 C. or higher, the higher temperatures, however, being detrimental to the purity of the product.

The advantages of this invention are not confined to completely eliminating the use of sulfuric acid, and it is possible through this invention to effect the condensation between chloralhydrate and chlorobenzene by employing a mixture of chlorosulfonic acid and sulfuric acid or chlorosuli'onic and fuming sulfuric acid (oleum) as illustrated by the following example: 82.7 parts by weight of chloralhydrate is placed in a suitable reactor equipped with stirrer, thermometer, gas exit tube, and dropping funnel. 58.3 parts by weight of chlorsulfonic acid is added with stirring at such a rate that the temperature of the reaction mixture does not exceed 10 C. When all the chloralhydrate crystals have dissolved and the evolution of HCl gas has virtually ceased, 112.5

' parts by weight of chlorbenzene is added with stirring to the reaction mixture at a rate such that the temperature does not exceed 20 C. From the dropping funnel, 143.0 parts by weight of 28% oleum (H2SO4.SO:) is added dropwise with vigorous stirring over a period of 10-30 minutes. Stirring is continued from 2-6 hours at 20 C. after the addition of the oleum is complete. The product is washed with water, filtered, and dried. Yield DDT=5060% of theory.

Although from the cost standpoint, it is now preferred to use chloralhydrate instead of anhydrous chloral, through the use of chlorsulfonic acid, this invention also lends itself to the condensation of anhydrous chloral (CClaCHO) with chlorbenzene. This reaction, also requires the metathetical quantity of chlorsulfonic acid, being, however, only one-half that required for an equivalent quantity of chloral hydrate. The course of this reaction is believed to be only slightly different from the mechanism proposed for the chloralhydrate process. The condensation of chloral with chlorbenzene in the presence of cblorsulfonic acid is believed to be representable by the following set of equations:

n cot-i=0 +001: cot-i001 cot-cool G01 l-BOQOH H coll-(1001 also.

The following example illustrates the use of anhydrous chloral: 73.7 parts by weight of anhydrous chloral is mixed with 112.5 parts by weight of chlorbenzene at 10 C. in a suitable reaction vessel equipped with thermometer, stirrer, gas exit tube, and dropping funnel. From the dropping funnel 58.3 parts by weight of chlorsuifonic acid is added dropwise over a period of 30 minutes keeping the temperature at 1020 C. After addition of the chlorsulfonic acid is complete, stirring is allowed to continue for an additional 5% hours at 10-20" C. The product is washed 3 times sulionic acid (1 moi part) with agitation. 2 moi 'parts of the appropriate hydrocarbomare added Condensation products obtained by the action of chlorsuljonic acid on chloralhydrate and aromatic hydrocarbons Aromauculggidrwmbon Product obtained 328? Per Cent 0 Per Cent H Per Cent 01 Per Cent Br Benzene B 01-62 found 59.0 iound 3.9 found 37.2 A} theory 58.9 theory 4.0 theory 37.3 C Cl:

Toluene H 74-76 found 61.). found 4.8 found34.8 A: theory 61.3 theory 4.8 theory 33.9

a CH -CC1: CH:

Brombenzene H 138-139 found 38.2 found 2.2 iound 22.80 Found 35.99

5 theory 37.9 theory 2.1 theory 24.0 theory 30.0- B C Cl: Br

p-dibrombenzene Br heavy not analyzed H oil BrOBr l-C Oh r Br O-diehlorbanzene Cl heavy not analyzed oil (7) 01 H at 040 C. with 2.9 parts by weight of chior- 76 Since other changes may be made in theforegoing processes and procedures, and diflerent embodiments of the invention will suggest themselves to those skilled in the art, it is intended that all matter described above be taken as illustrative and not in a limiting sense.

We claim:

1. In the reaction of the member of the group 70 consisting of anhydrous chloral and chloral hydrate with two mols of chloral benzene to form 2,2 bis(p chlorophenyl) 1,1,1 trichloroethane. the improvement which consists in carrying out the reaction in the presence of a stoichiometric amount oi. chlorosulfonic acid.

2. The method of making 2,2-bis (p-chlorphenyl) 1,1,1-trichloroethane, which comprises, adding about 1 part by weight oi chlorsulionic acid to about 1.42 parts by weight of chloralhydrate while keeping the reaction temperature between about 0 C. to 10 C., stirring the reaction mass until all of the chloralhydrate crystals have dissolved, adding about 1.93 parts by weight of chlorbenzene to the reaction mass while maintaining the temperature at about 20 0.. adding about 1 part by weight of chlorsulionic acid to the reaction mass and separating the yield of 2,2-bis (p-chlorphenyl) 1,1,1-trichloroethane from the reaction mass.

3. The method of making 2,2-bis (p-chlorphenyl) 1,1,1-trichloroethane, which comprises. adding about 1 part by weight of chlorsultonic acid to about 1.42 parts by weight of chloralhydrate while keeping the reaction temperature between about 0 C. to 10 C., after all the chloraihydrate crystals have dissolved and the evolution of HCl gas has substantially ceased adding about 1.93 parts by weight of chlorbenzone to the reaction mass while maintaining the temperature of the mass not in excess of about 20 C., slowly adding about 2.45 parts by weight of 28% oleum (112804503) with vigorous stirring, stirring the reaction mass from 2 to 6 hours at about 20 C. after addition of said oleum, and separating the yield of 2,2-bis (p-chlorphenyl) 1,1,1-trichloroethane from the reaction mass.

4. The method of making 2,2-bis (p-chlorphenyl) 1,1,1-trichloroethane, which comprises. mixing about 1.26 parts by weight of anhydrous chloral with about 1.93 parts by weight of chlorbenzcne at about 10 0., adding about 1 part by weight of chlorsulfonic acid to the reaction mass while maintaining the temperature thereof between about 10-20 C., stirring the reaction mass during the addition of the chlorsulionic acid and for a substantial period after the addition, and separating the yield of 2,2- bis (p-chlorphenyl) 1,1,1-trich1oroethane from the reaction mass.

5. The method of making 2,2-bis (p-chlorphenyl) 1,1,1-trichloroethane which comprises reacting chlorosulfonic acid, chlorobenzene, and

8 perature within a range of between minus 50 C. and plus 39 C. until the crystals have become dissolved in and hydrochloric acid has been evolved from the mixture, adding chlorobenzene to the solution thus formed at a rate adapted to maintain the solution at a temperature of about 20 C. while the liquid is being stirred then adding additional chlorosulfonic acid to the solution until H3804 is produced and 2,2-bis (p-chlorphenyl) 1,1,1-trichloroethane commences to precipitate from the solution, stirring said mixture until the reaction is substantially thereafter separating the precipitated 2,2-bis (pchlorphenyl) 1,1,1-trichloroethane from the mixture, the chlorobenzene and chloral hydrate being in the mol ratio of 2:1.

6. The method of making 2,2-bis-(p-chlorphenyl) 1,1,1-trichioroethane, said method consisting of slowly adding chlorosuifonic acid to chloral hydrate crystals until said crystals have been dissolved by the chlorosulionic acid, slowly adding chlorobenzene to the solution thus formed until said 2,2-bis (p-ehlorphenyl) 1,1,1-trichloroethane commences to precipitate visibly from sai solution, then slowly adding to the precipitating solution more chlorosultonic acid until there is a heavy precipitation of said 2,2-

chloral hydrate together by slowly adding chlorosulionic acid to chloral hydrate crystals while stirring'the mixture and maintaining its tembis (p-chlorphenyi) 1,1,1-trichloroethane and finally separating said 2,2-bis (p-chlorphenyl) 1,1,1-trich1oroethane from said solution, the chlorobenzene and chloral hydrate being in the mol ratio of 2:1.

7. The method or claim 6, in which said mixture and solution are stirred and maintained at a temperature of between minus 50 C. and plus 39 0., until the 2,2-bis (p-chlorphenyl) 1,1,1- trichloroethane is heavily precipitated.

WALTER H. C. RUEGGEBERG. WALTER A. COOK.

REFERENCES orran The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,054,140 Segessemann Sept. 15, 1936 2,259,723 Ballard et al Oct. 21, 1941 2,329,074 Muller Sept. 7, 1943 2,349,211 Tulleners May 16, 1944 complete, 

1. IN THE REACTION OF THE MEMBER OF THE GROUP CONSISTING OF ANHYDROUS CHLORAL AND CHLORAL HYDRATE WITH TWO MOLS OF CHLORAL BENZENE TO FORM 2,2-BIS(P-CHLOROPHENYL) 1,1,1-TRICHLOROETHANE, THE IMPROVEMENT WHICH CONSISTS IN CARRYING OUT THE REACTION IN THE PRESENCE OF A STOICHIOMETRIC AMOUNT OF CHLOROSULFONIC ACID. 